A shortening is a plastic fat, which is a mixture of triglycerides having widely different melting points. Fat crystals in a shortening are held together by internal cohesive forces and liquid oil is enmeshed in the structure. Shortenings are used in cakes to impart tenderness, texture, and crumb and promote increase in volume by shortening the strands of gluten, which in the absence of fat would form a tough meshwork structure. Shortenings assist the leavening in the oven of the cake of non-fermented doughs, where rapid rising by means of gas from baking powder and vapour is required. Shortening also acts as a foaming/whipping agent in the aeration process of batters and doughs to achieve the required volume of the baked products. Emulsifiers, such as lecithin, mono- and diglycerides of fatty acids, propylene glycol mono- and diesters of fatty acids, diacetyl tartaric acid esters of mono- and diglycerides of fatty acids may be used in conjunction with shortenings. The emulsifiers are included in order to provide tenderization, anti-staling, lubrication, and aeration of doughs. Various emulsifiers included in bakery products either contain triglycerides, and/or are derived from triglycerides, thus contributing to the fat content in the cake.
Commercially available emulsified or stabilized shortenings contain 2-5% of emulsifier, except that when the emulsifier is mono- and diglyceride higher levels, i.e., 6%, are included.
In light of the rising consumer demand for low fat, low calorie products, food scientists are faced with a challenging task of producing a baked product which is tender and breaks apart easily and has a good height but which contains a reduced amount of fat. Although the fat content of the cake may be lowered by employing fat blends, e.g. margarines containing 16-20% water, a further reduction in fat is desirable. If fat is replaced with an increased amount of water, however, a number of problems are observed including weakening of the batter and decreased aeration and cake volume.
U.S. Pat. No. 4,351,852 (Rule et al.) discloses a cake batter including flour and sugar intimately blended with a mono- and diglyceride emulsifier, the emulsifier having specifically defined di- and triglyceride levels. The emulsifier is marketed under the trademark Dur-lo.RTM. (Van den Bergh Foods Corp.). The emulsifier may be employed in an amount of 5% or more with a conventional amount of shortening, or the emulsifier may be employed alone in an amount of 15% (flour weight basis), with no additional lipids or other emulsifiers. Rule et al. disclose the actual triglyceride content in a cake batter or mix can be as low as about 3.5% (flour weight basis).
U.S. Pat. No. 4,818,553 (Holsher et al.) discloses a method of preparing bakery products which involves combining a water-in-oil emulsion to serve as a shortening and at least one further component selected from flour, eggs, leavening agents, sugar, and mixtures of these materials. The emulsion contains 15-70% fat phase and 5-60% by weight, based on the total emulsion, of a water-dissolved humectant. The humectant is selected from the group consisting of glucose, fructose, mannose, galactose, talose, lactose, sucrose, maltose, maltodextrins, polydextrose, glycerol, sorbitol, propylene glycol, and mixtures thereof. The fat phase may optionally include an emulsifier, such as mono- and diglyceride mixture, or mixtures of mono- and diglycerides with lecithin. Typically, small amounts (i.e., below 0.5% by weight of the emulsion) of the emulsifier are included. It is said that it is important for the fat phase to constitute a continuous phase of the emulsion, since "water-continuous emulsions cannot be used satisfactorily in traditional cake preparation involving first aerating the emulsion with sugar to produce an aerated cream which is subsequently mixed with eggs and flour to produce the batter." Examples of the Holscher patent describe water-in-oil emulsions containing at least 40% fat. Unfortunately, at particularly low fat levels, i.e. at fat levels below about 40%, preparation of water-in-oil emulsion becomes difficult: any minor fluctuation in processing, e.g. cooling, can change the emulsion to oil-in-water. Therefore, an oil-in-water rather than a water-in-oil emulsion is desirable which could be used as a low fat replacement for shorthening.
Accordingly, it is an object of the present invention to provide a reduced fat shortening substitute while avoiding the above-mentioned drawbacks.
It is another object of the invention to provide a reduced fat oil-in-water emulsion which can be used as a shortening replacement.
It is another object of the invention to provide a shortening substitute which may be employed to attain up to 80% fat reduction in a baked product.
It is yet another object of the invention to provide a shortening replacement product which is similar to shortening in texture, appearance and functionality, yet contains no more than 40% fat, or preferably no more than about 20% fat.
It is still another object of the invention to lower the fat content in a baked product without adversely affecting the properties of a baked product and without altering the recipe for the preparation of the baked product.
These and other objects of the invention will become more apparent from the detailed description and examples which follow.